<?php

namespace application\Comm;

//验证码类  
class Captcha {

    private $charset = 'abcdefghjkmnprstuvwxyzABCDEFGHJKMNPRSTUVWXYZ23456789';    //随机因子  
    private $code;                            //验证码  
    private $codelen = 4;                    //验证码长度  
    public $width = 130;                    //宽度
    public $height = 50;                    //高度
    private $img;                                //图形资源句柄  
    private $font;                                //指定的字体  
    private $fontsize = 16;                //指定字体大小
    private $fontcolor;                        //指定字体颜色  

    //构造方法初始化  

    public function __construct() {
        $this->font = 'css/arial.ttf';
    }

    //生成随机码  
    private function createCode() {
        $_len = strlen($this->charset) - 1;
        for ($i = 0; $i < $this->codelen; $i++) {
            $this->code .= $this->charset[mt_rand(0, $_len)];
        }
    }

    //生成验证码背景  
    private function createBg() {
        $this->img = imagecreatetruecolor($this->width, $this->height);
        $color = imagecolorallocate($this->img, mt_rand(157, 255), mt_rand(157, 255), mt_rand(157, 255));
        imagefilledrectangle($this->img, 0, $this->height, $this->width, 0, $color);
    }

    //生成验证码文字  
    private function createFont() {
        $_x = $this->width / $this->codelen;
        for ($i = 0; $i < $this->codelen; $i++) {
            $this->fontcolor = imagecolorallocate($this->img, mt_rand(0, 156), mt_rand(0, 156), mt_rand(0, 156));
            imagettftext($this->img, $this->fontsize, mt_rand(-30, 30), $_x * $i + mt_rand(1, 5), $this->height / 1.4, $this->fontcolor, $this->font, $this->code[$i]);
        }
    }

    //生成线条、雪花  
    private function createLine() {
        for ($i = 0; $i < 6; $i++) {
            $color = imagecolorallocate($this->img, mt_rand(0, 156), mt_rand(0, 156), mt_rand(0, 156));
            imageline($this->img, mt_rand(0, $this->width), mt_rand(0, $this->height), mt_rand(0, $this->width), mt_rand(0, $this->height), $color);
        }
        for ($i = 0; $i < 100; $i++) {
            $color = imagecolorallocate($this->img, mt_rand(200, 255), mt_rand(200, 255), mt_rand(200, 255));
            imagestring($this->img, mt_rand(1, 5), mt_rand(0, $this->width), mt_rand(0, $this->height), '*', $color);
        }
    }

    //输出验证码图片 
    private function outPut() {
        header('Content-type:image/png');
        imagepng($this->img);
        imagedestroy($this->img);
    }

    //对外生成  
    public function doimg() {
        $this->createBg();
        $this->createCode();
        $_SESSION['captcha'] = $this->getCode();
        $this->createLine();
        $this->createFont();
        $this->outPut();

    }

    //获取验证码  
    public function getCode() {
        return strtolower($this->code);
    }

}
